An important salient feature of chronic head and neck pain syndromes is muscle dysfunction. Whatever the origin of pain (trauma, pathology of the cervical spine, etc.), patients frequently develop lateral, anterior and posterior neck muscle activation imbalance, muscle fatigue, muscle shortening, and over-contraction of agonist and antagonist muscles. Subsequently, muscle hyperalgesia and reduced neck range of motion is induced. This hyperalgesia is a part of a vicious cycle of pain mechanism. Mobilization and/or physical therapy are effective for some patients, whereas for other patients, biofeedback relaxation techniques are helpful. In many cases, the therapeutic protocol involves a set of motions that are repeated cyclically. A number of devices have been developed that are designed to provide at least some degree of automation to the therapeutic protocol.
U.S. Pat. No. 5,320,641 discloses a device for spinal rehabilitation, allowing a limited elevation/depression of different parts of the spinal column, not necessarily the cervical spine. The device allows only one degree of freedom, no true feedback from the patient. It mainly relates to post operative treatment and not for the treatment of headache and/or neck pain. It is mainly focused on enlarging the flexion/extension range of movement of the neck post trauma, post surgery.
Japanese Pat. No. 5,038,307 describes a seat for a vehicle having variable air pressure mats within. Electromyograph signals are taken of the driver's body. When these signals indicate that the driver is tired, the air pressure of the seat is varied. However this variation is not intended to relax the driver but rather to increase his level of alertness while driving. The pattern of inflation is therefore not adapted to decrease the electromyographic potentials indicating muscle tension by use of feedback. Since the head and neck are not specifically stimulated by this cradle, it is unlikely that the cradle is adapted to provide relief from headaches or muscle tension. It does not reposition the head and neck in a manner similar to physical therapy adjustment. Finally, it does not determine the ideal degree of movement for each individual, nor does it maintain a computerized record of such.
U.S. Pat. No. 5,320,641 discloses a computer-controlled physical therapy device. This device is designed for treatment of a patient's back. It provides support for the back and the option of providing a predetermined pivoting (axial) motion. The actuators for the pivoting motion are computer controlled. This device makes no provision for rotational motion of the patient, and changes in the treatment protocol are performed by direct keyboard input to the computer.
U.S. Pat. No. 5,578,060 discloses an interactive physical therapy apparatus. This apparatus likewise provides for computer control. An operator can input into the computer specific treatment parameters, in particular, which body part is to be selected for treatment.
There remains, however, a long-felt need for a physical therapy system that permits input of treatment protocols (e.g. the direction and duration of the motions of the treatment apparatus) by means other than direct input of desired parameters; in which the control system is able to provide a treatment protocol for motions with six degrees of freedom (three translational and three rotational); and which provides the option of true feedback, in which the control apparatus modifies the treatment protocol according to parameter's related to the state of the patient during the course of the treatment.